COVID-19 has been found to cause blood clots, which can occur throughout the body in the form of a stroke, pulmonary embolism (clotting in the lungs), and deep vein thrombosis (clotting in the veins, typically in the lower body), for example. One small study found that 31 percent of COVID-19 patients experienced clotting, and experts are recommending patients take anticoagulants even after being discharged from the hospital.